Modelling strategies of prestressing tendons and reinforcement bars in concrete structures
Résumé
This contribution presents an original approach to improve the modeling of steel rebars and prestressing tendons in concrete structures at a reduced cost. Classical 1D meshes and models typically used for civil engineering applications tend to provoke strain localization due to the geometrical singularity and are thus unable to reproduce local mechanical effects. Complete 3D models can be applied in some cases, however their accuracy at the local scale comes at the cost of engineering work on the meshes, especially for complex structures. The 1D-3D model presented in this contribution generates an equivalent volume for the steel bars, based on existing 1D models. Its 3D stiffness and stress state are computed, and then condensed on its interface with the concrete. The condensed degree of freedom are then linked to the surrounding concrete elements by kinematic relations. The presented approach is validated on different representative cases, and is able to predict the 3D effects of the bars and tendons at the local scale. In particular it provides the representativeness and mesh stability of a full 3D model, without the need for a complex mesh.